System and method for adjusting brightness of rear seat entertainment monitor of vehicle in conjunction with open angle of monitor

ABSTRACT

The present invention provides a system and method for adjusting the brightness of a rear seat entertainment monitor for the rear seat passengers of a vehicle in conjunction with the open angle of the monitor. The brightness adjustment system of the present invention includes a monitor open angle input unit, a control unit, an image processing unit and a Liquid Crystal Display (LCD) panel unit. The monitor open angle input unit outputs a gearing amount corresponding to a current open angle of the rear seat entertainment monitor of the vehicle. The control unit calculates the current open angle of the monitor using the gearing amount, received from the monitor open angle input unit, and outputs a control signal required to set parameter values for an output screen image, corresponding to the calculated current monitor open angle. The image processing unit outputs a screen image of the monitor using corrected parameter values for an output screen image, in response to the control signal output from the control unit. The LCD panel unit projects the image, which has been output through the image processing unit, onto a screen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Korean Application No. 10-2005-0097921, filed on Oct. 18, 2005, with the Korean Intellectual Property Office, the disclosure of which is fully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to rear seat entertainment systems and, more particularly, to systems and methods for improving the brightness of images on a rear seat entertainment monitor as seen from different viewing angles.

BACKGROUND OF THE INVENTION

Traditionally, Liquid Crystal Displays (LCDs) offer a limited viewing angle. Depending on the viewer's location, the displayed screen state can vary considerably; looking at the display panel from the sides, top, or bottom often results in tremendous color distortions or loss of brightness. An illustration of various viewing angles and a table of their corresponding brightness are shown in FIG. I and FIG. 5, respectively.

Referring to FIG. 1, when the monitor is viewed at a 90° angle, the displayed screen state is at its optimal; in other words, a brightness value of 300 cd/m² set in the monitor would yield a displayed screen state with a brightness value of 300 cd/m² as measured from Eye3's perspective. However, at a viewing angle of 120°, the brightness value of the displayed screen state as measured from Eye4 drops to 200 cd/m² and the displayed screen state is noticeably darker. This phenomenon grows increasingly worse as the viewing angle deviates increasingly further from 90°, e.g. when the monitor is viewed at six o'clock (a viewing angle of 0°) and twelve o'clock (a viewing angle of 180°). In the context of a vehicular entertainment system, the problem is even greater due to the relative confinement of the rear-seat passengers to their seating positions, making it difficult for multiple passengers to simultaneously view the images in their optimal or near-optimal state.

As such, there is a need in the art for systems and methods that can correct the brightness of an LCD panel at wider viewing angles.

SUMMARY OF THE INVENTION

The present invention provides systems and methods for adjusting the brightness of a Rear Seat Entertainment (RSE) monitor in an automotive vehicle based on the open angle of the monitor.

In some embodiments of the present invention, a system for adjusting brightness of a rear seat entertainment monitor of a vehicle based on the open angle of the monitor includes a monitor open angle input unit, a control unit, an image processing unit and a Liquid Crystal Display (LCD) panel unit. The monitor open angle input unit outputs a gearing amount, which corresponds to the current open angle of the rear seat entertainment monitor of the vehicle. The control unit receives this gearing amount from the monitor open angle input unit and uses it to calculate the current open angle of the monitor, and outputs a control signal required to set parameter values for an output screen image based on the monitor's calculated open angle. In response to the control signal output from the control unit, the image processing unit outputs a screen image of the monitor using the corrected parameter values for the output screen image. The LCD panel unit then projects the image, which has been output through the image processing unit, onto a screen.

In some embodiments of the present invention, the method of adjusting brightness of a rear seat entertainment monitor of a vehicle based on the open angle of the monitor comprises: a) receiving from a control unit a gearing amount corresponding to an open angle of the monitor; b) calculating a current open angle of the monitor using the received gearing amount; setting parameter values for an output screen image corresponding to the current open angle after the open angle of the monitor has been calculated; c) projecting the screen image from an image processing unit onto a Liquid Crystal Display (LCD) panel unit; d) adjusting brightness of a backlight of the LCD panel unit using the parameter values set by the control unit; and e) completing adjustment of the screen brightness of the monitor.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the present invention, reference should be made to the following detailed description with the accompanying drawings, in which:

FIG. 1 illustrates various viewing angles of a typical LCD monitor;

FIG. 2 illustrates a block diagram of the system of the present invention;

FIG. 3 illustrates the mechanism by which the open angle of the monitor is determined; FIG. 3A illustrates the open state of the monitor of the system according to the present invention; FIG. 3B is a close-up view of portion “O” according to an embodiment of the present invention;

FIG. 4 is a flow diagram outlining the steps of the method of the present invention;

FIG. 5 is a comparison of the measured brightness of a conventional monitor and the measured brightness of a monitor corrected by the system according to an embodiment of the present invention; FIG. 5A is a table of brightness values of a conventional monitor and FIG. 5B is a table of brightness values of a monitor corrected by the system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Herein below, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

The present invention provides a system, shown in FIG. 2, that adjusts the brightness of an RSE monitor in conjunction with the open angle of the monitor. In preferred embodiments of the present invention, the system includes a monitor open angle input unit 10, a control unit 20, an image processing unit 30 and a Liquid Crystal Display (LCD) panel unit 40.

The monitor open angle input unit 10 outputs a gearing amount which corresponds to the current open angle a of the RSE monitor 100, as illustrated in FIG. 3A. The control unit 20 calculates the current open angle of the monitor using the gearing amount received from the monitor open angle input unit 10, and then outputs a control signal required to set parameter values for an output screen image, corresponding to the calculated current monitor open angle. The image processing unit 30 outputs the screen image of the monitor using corrected parameter values for the output screen image, in response to the control signal output from the control unit 20. The LCD panel unit 40 projects the image output from the image processing unit 30 onto the screen.

In the system illustrated in FIG. 2, the values of various parameters of the output screen image of the monitor corresponding to the open angle of the monitor, e.g. brightness, contrast, hue, gamma and color saturation of a monitor screen image, and a voltage value for the backlighting intensity of the LCD panel unit, are stored in the control unit 20 in the form of a map table 25.

Further, the image processing unit 30 includes a brightness adjustment register unit 31 for adjusting brightness, a contrast adjustment register unit 32 for adjusting contrast, a hue adjustment register unit 33 for adjusting hue, a gamma adjustment register unit 34 for adjusting gamma, a saturation adjustment register unit 35 for adjusting color saturation, and a Direct Current (DC) inverter circuit unit 36 for adjusting a voltage value for the backlighting intensity of the LCD panel unit. As previously mentioned, the brightness, contrast, hue, gamma and color saturation are parameter values for the output screen image of the monitor.

Further, a backlight lamp unit 50 is provided in the LCD panel unit 40 to adjust the brightness of the LCD panel.

Further, the monitor open angle input unit 10 is manufactured to have a gear-hinge structure to output the number of clicks by which a gear has been rotated according to the current open angle of the monitor.

As shown in FIG. 3B, the control unit 20 determines the number of clicks by which a gear 7 is rotated in the direction of an arrow from a reference point A to thereby determine the current open angle of the monitor. In other words, the control unit 20 receives the number of clicks of the gear, i.e. gearing amount, corresponding to the open angle of the monitor and calculates the open angle of the monitor using the number of clicks by which the gear is rotated from the reference point.

In preferred embodiments of the present invention, the monitor open angle input unit 10 comprises a rotatable gear-hinge structure, designated as portion “O” in FIG. 3A. As shown in FIG. 3B, a preferred embodiment of the gear-hinge structure comprises 8 teeth A to H on the basis of reference point A and is rotatable at an angle of 45° per tooth. However, alternate configurations of the gear-hinge structure, e.g. different number of teeth at different intervals with different gear amount per turn of the structure, can be used to achieve the object of the present invention. These features constitute the mechanism by which the open angle of the monitor is determined. The open angle of the monitor can be determined based on the gear amount, i.e. number of clicks of the gear, of the gear-hinge structure from a reference point. For example, using the monitor's closed position as the reference point, if the number of gear clicks is equal to 36 and the gear rotates five teeth from the reference point, then the current open angle of the monitor is determined to approximate 50°. In this manner, the current open angle of the monitor a between the cover 2 of the monitor and a monitor screen 4 can be determined based on the number of gear clicks from a reference point.

The method of adjusting the brightness of a rear seat entertainment monitor in conjunction with the open angle of the monitor according to an embodiment of the present invention, using the system having the above construction, is described with reference to the flowchart of FIG. 4 based on FIG. 2.

As shown in FIG. 4, the control unit 20 receives a gearing amount, i.e. the number of clicks by which the gear is rotated, corresponding to the current open angle of the monitor from the monitor open angle input unit 10 at step S10, and then calculates the current open angle of the monitor at step S20. In the above operation, the calculation of the current open angle of the monitor is performed using the number of clicks by which the gear is rotated from the reference point, as described above with reference to FIGS. 3A and 3B.

After the current open angle of the monitor has been calculated at step S20, the control unit 20 sets parameter values for an output screen image corresponding to the current open angle of the monitor, e.g. brightness, contrast, hue, gamma, and color saturation required for outputting the screen image of the monitor, and a voltage value required for adjusting the backlighting intensity of the LCD panel unit, using the stored map table at step S30.

In some embodiments of the present invention, the control unit 20 is a Micom means that adjusts various parameters, e.g. brightness, contrast, chroma, hue, gamma and saturation, of the LCD. It should be noted that alternative means capable of serving the above function can be used to achieve the object of the present invention. The Micom means comprise a memory wherein map table 25 is stored. The map table 25 contains data in the form of a table containing parameter values, e.g. brightness, contrast, chroma, hue, gamma, and saturation, etc. according to various open angles. To adjust the brightness of the screen image outputted on the LCD panel, the control unit 20 comprises a processor that can access data from the map table and thus retrieve the appropriate signals for brightness, contrast, chroma, hue, gamma, and saturation given the open angel of the monitor. The control unit 20 then transmits these signals to the appropriate registers in the image processing unit 30. Likewise, an appropriate voltage value signal of the backlight lamp unit is selected based on the open angle of the monitor and transmitted to the DC inverter circuit of the image processing unit 30, thereby altering or correcting the brightness of the screen image as outputted on the LCD panel.

In summary, after respective parameter values have been set at step S30, correction control signals for respective parameter values outputted from the control unit 20 are inputted to the image processing unit 30, thereby directing the correction of the respective parameter values. After respective parameter values have been corrected, the image processing unit 30 projects a screen image, in which the respective parameter values have been corrected, onto the LCD panel unit 40, and adjusts the backlighting brightness of the backlight lamp unit 50 in the LCD panel unit 40. In this manner, the screen image brightness of the monitor is adjusted based on the open angle of the monitor at steps S40 and S50.

A demonstration of the extent to which the brightness of the screen images can be adjusted at various viewing angles is provided in FIG. 5. As shown therein, significant improvement in brightness is achieved for viewing angles ranging from 0 to 30° and from 150 to 180° as compared with the image brightness of conventional monitor. These results are based on the fact that the brightness of the monitor is optimal at 318 cd/m² when the open angle of the monitor is 90°.

As is apparent from the foregoing, there is an advantage in a system and method for adjusting the brightness of the RSE monitor of a vehicle in conjunction with the open angle of the monitor of the present invention, in that it can provide a bright image even at a non-perpendicular viewing angle. Thus, the present invention saves users from the inconvenience of having to adjust the open angle of the monitor each time, thereby effectively extending the useful viewing range of the monitor.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be limited to the foregoing embodiments. Those skilled in the art will appreciate that changes or modifications to the embodiments can be made without departing from the scope and spirit of the present invention. 

1. A system for adjusting brightness of a rear seat entertainment monitor of a vehicle based on an open angle of the monitor, comprising: a monitor open angle input unit for outputting a gearing amount corresponding to a current open angle of the rear seat entertainment monitor of the vehicle; a control unit for calculating the current open angle of the monitor using the gearing amount, received from the monitor open angle input unit, and outputting a control signal required to set parameter values for an output screen image, corresponding to the calculated current monitor open angle; an image processing unit for outputting a screen image of the monitor using corrected parameter values for an output screen image, in response to the control signal output from the control unit; and a Liquid Crystal Display (LCD) panel unit for projecting the image, which has been output through the image processing unit, onto a screen.
 2. The system as recited in claim 1, wherein the monitor open angle input unit comprises a gear-hinge structure to output the number of clicks by which a gear is rotated, said number corresponding to the current open angle of the monitor.
 3. The system as recited in claim 1, wherein the control unit stores parameter values for the output screen image of the monitor corresponding to open angles of the monitor in the form of a map table.
 4. The system as recited in claim 1, wherein the image processing unit comprises a brightness adjustment register unit for adjusting brightness, a contrast adjustment register unit for adjusting contrast, a hue adjustment register unit for adjusting hue, a gamma adjustment register unit for adjusting gamma, a saturation adjustment register unit for adjusting color saturation, and a Direct Current (DC) inverter circuit unit for adjusting a voltage value for backlighting intensity of the LCD panel unit, the brightness, contrast, hue, gamma and color saturation being parameter values for the output screen image of the monitor.
 5. The system as recited in claim 1, wherein the LCD panel unit comprises a backlight lamp unit for adjusting brightness of the LCD panel unit.
 6. A method of adjusting brightness of a rear seat entertainment monitor of a vehicle based on an open angle of the monitor, comprising the steps of: receiving a gearing amount from a control unit corresponding to a current open angle of the monitor; calculating the current open angle of the monitor using the received gearing amount; setting parameter values for an output screen image corresponding to the current open angle after the open angle of the monitor has been calculated; projecting the screen image from an image processing unit onto a Liquid Crystal Display (LCD) panel unit and adjusting brightness of a backlight of the LCD panel unit, using the parameter values set by the control unit; and completing adjustment of the screen brightness of the monitor.
 7. The method as recited in claim 6, wherein the control unit stores parameter values for the output screen image of the monitor corresponding to open angles of the monitor, in a format of a map table.
 8. The method as recited in claim 6, wherein the image processing unit adjusts brightness, contrast, hue, gamma and color saturation, which are parameter values for the screen image to be output through the monitor, and a voltage value for backlighting. 